(a) Technical Field
The present invention relates to a radiant heat plate and a battery cell module having the same. More particularly, it relates to a radiant heat plate and a battery cell module having the same, which can deal with the volume change of a battery cell and can effectively radiate heat accumulated in the battery cell module.
(b) Background Art
Generally, local temperature differences and high temperatures may occur in batteries of electric vehicles due to the amount of heat generated by the battery's high-output, high-speed, and repetitive charging and discharging, causing thermal runaway that hinders the efficiency and stability of batteries. The thermal runaway results from deficiency of heat radiation and diffusion capacity to the outside of the batteries compared to heat generated within batteries.
Lithium secondary batteries, which have a working voltage of about 3.6 V or more, are being used as power sources for portable electronics, and in high-power hybrid vehicles by being connected in series to each other. The lithium secondary batteries have a working voltage three times higher than that of nickel-cadmium batteries or nickel-metal hybrid batteries, and have a better energy density per unit weight as well.
Various types of lithium secondary batteries can be manufactured. Recent lithium secondary batteries of a pouched type with flexibility are relatively flexible in in shape and therefore are ideal in automotive applications.
Battery cells constituting a typical pouched-type lithium secondary battery include a battery part and a pouched-type case having a space receiving the battery part. The battery part includes an anode plate, a separator, and a cathode plate that are sequentially disposed and wound in one direction, or includes a plurality of anode plates, separators, and cathode plates stacked in a multi-layered structure. Also, the case can be flexibly bent due to its excellent formability.
The pouched-type battery cells may vary in volume due to intercalation/deintercalation of lithium ions to/from electrode material during charging/discharging as discussed in Journal of Power Sources, by J. H. Lee et al. 119-121 (2003) 833-837 which is hereby incorporated by reference in its entirety.
The damage of the separator due to expansion of the electrode plate in the battery cell incurs generation of internal resistance, increase of voltage, and reduction of battery capacity. Also, when the volume of a battery cell in a typical battery system increases, a channel formed between two battery cells in a battery cell unit decreases in size, reducing the cooling effect rather than a channel formed between modules. Accordingly, heat generation between battery cells due to rising temperatures of adjacent battery cells is accelerated. This causes a rapid reduction in the battery performance as a result.
In addition, when the volume expansion of the battery cell is severe, the case may be damaged thereby causing leakage of the electrolyte and gas from inside the battery. Furthermore, since the battery cell module is structured by stacking a plurality of battery cells (or unit cells), the volume expansion of the battery cell, gas leakage, or even explosion of a cell may cause damage to the cells surrounding it.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.